%0 Journal Article
%T Interference of Light in a Michelson-Morley Interferometer: A Quantum Optical Approach
%A £¿. Langangen
%A A. Vaskinn
%A B.-S. Skagerstam
%J International Journal of Optics
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/408067
%X The temporal coherence interference properties of light as revealed by single detector intensity measurements in a Michelson-Morley interferometer (MMI) is often described in terms of classical optics. We show, in a pedagogical manner, how such features of light also can be understood in terms of a more general quantum-optics framework. If a thermal reference source is used in the MMI local oscillator port in combination with a thermal source in the signal port, the interference pattern revealed by single detector intensity measurements shows a distinctive dependence on the differences in the temperature of the two sources. A related method has actually been used to perform high-precision measurements of the cosmic microwave background radiation. The general quantum-optics framework allows us to consider any initial quantum state. As an example, we consider the interference of single photons as a tool to determine the peak angular-frequency of a single-photon pulse interfering with a single-photon reference pulse. A similar consideration for laser pulses, in terms of coherent states, leads to a different response in the detector. The MMI experimental setup is therefore an example of an optical device where one, in terms of intensity measurements, can exhibit the difference between classical and quantum-mechanical light. 1. Introduction In 2006, Smoot and Mather shared the Nobel Prize in physics ¡°for their discovery of the black-body form and anisotropy of the cosmic microwave background radiation (CMB)¡± [1]. These exciting discoveries were a breakthrough in modern cosmology by the CMB anisotropy and the strong validation of the black-body spectrum as predicted by the Big Bang theory. The discovery of the black-body form of the CMB spectrum and the high-precision measurement of the CMB temperature (see e.g., [2]) relied heavily on the so-called Far-Infrared Absolute Spectrophotometer (FIRAS) [3] on board the Cosmic Background Explorer (COBE) [4, 5]. In short, the FIRAS is a Michelson-Morley interferometer enabling a comparison of the interference patterns between an observed source and a reference black-body source on board the COBE satellite. In this paper, we will make use of Glauber¡¯s theory for photon detection [6, 7] (for a guide to the early literature see e.g., [8¨C10] and for textbook accounts see e.g., [11¨C14]) together with elementary quantum mechanics to show how the principles of the FIRAS can be understood in a straight-forward manner using a quantum-optics frame-work. Interference phenomena in classical optics are described in terms of
%U http://www.hindawi.com/journals/ijo/2012/408067/